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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
3-15-2006 to 318-2006
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Well documented, GLP and OECD 201 guideline study.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2006
Report date:
2006

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
no
Remarks:
The study was conducted according to the guideline in effect at time of study conduct.
Qualifier:
according to guideline
Guideline:
EU Method C.3 (Algal Inhibition test)
Deviations:
no
Remarks:
The study was conducted according to the guideline in effect at time of study conduct.
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Reference substance name:
DBC80
IUPAC Name:
DBC80
Constituent 2
Chemical structure
Reference substance name:
-
EC Number:
481-150-8
EC Name:
-
Cas Number:
500011-86-9
Molecular formula:
C9H5BrClN3O2
IUPAC Name:
3-bromo-1-(3-chloropyridin-2-yl)-1H-pyrazole-5-carboxylic acid
Constituent 3
Reference substance name:
1H-Pyrazole-5-Carboxylic Acid, 3-Bromo-1-(3-Chloro-2-Pyridinyl)-
IUPAC Name:
1H-Pyrazole-5-Carboxylic Acid, 3-Bromo-1-(3-Chloro-2-Pyridinyl)-
Details on test material:
- Name of test material (as cited in study report): IN-CBD80
- Molecular formula: C9H5BrCIN3O2
- Physical state: Tan powder
- Analytical purity: 96.75
- Lot/batch No.: 008
- Expiration date of the lot/batch: 7/22/08
- Stability under test conditions: Stable
- Storage condition of test material: Stored in the dark at room temperature.
- Other: Supplied by DuPont Company, Stine- Haskell Research Center Crop Protection Products, Newark, Deleware.

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations: High and low concentrations, positive and negative controls.
- Sampling method: Collected in glass containers at the beginning and end of the study.
- Sample storage conditions before analysis: Not specified, sent to Department of Analytical Chemistry for analysis.

Test solutions

Vehicle:
yes
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Controls: Negative and vehicle controls.
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): Acetone
- Concentration of vehicle in test medium (stock solution and final test solution(s) including control(s)): <0.1 mL/L
- Evidence of undissolved material (e.g. precipitate, surface film, etc): No

Test organisms

Test organisms (species):
Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)
Details on test organisms:
TEST ORGANISM
- Common name: Pseudokirchneriella subcapitata
- Source (laboratory, culture collection): In-house culture, original source Marinco Bioassy Laboratory.
- Age of inoculum (at test initiation): 3 days



Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Post exposure observation period:
None

Test conditions

Hardness:
Not applicable
Test temperature:
20.9-23.6° Celcius
pH:
8.01-9.54
Dissolved oxygen:
Not applicable
Salinity:
Not applicable
Nominal and measured concentrations:
Nominal- Control, Vehicle control, 3.5, 6.3, 11.4, 20.6, 37.1, 66.7, and 120 mg/L.
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): Closed, with non-absorbant cotton plugs.
- Material, size, headspace, fill volume: Glass 250 mL conical flasks, 100 mL fill volume
- Initial cells density: 71667 cells/mL
- Control end cells density: 1,876,667 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3
- No. of vessels per vehicle control (replicates): 3


GROWTH MEDIUM
- Standard medium used: yes



TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Distilled water
- Culture medium different from test medium: no


OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: yes, to 8.1 with 0.1 N HCl or 0.1 N NaOH
- Photoperiod: Continuous
- Light intensity and quality: 7900-7985 lux


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Growth rate and percent inhibition, at 0, 24, 48 and 72 hours.
- Determination of cell concentrations: Visual count using an Improved Neubaur Haemocytometer and microscope.


TEST CONCENTRATIONS
- Range finding study concentrations: 15, 30, 60 and 120 mg/L
- Results used to determine the conditions for the definitive study: Yes
Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
other: EyC50
Effect conc.:
54.49 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
cell number
Remarks on result:
other: 95% CL 54.063-54.917 mg/L
Duration:
72 h
Dose descriptor:
other: ErC50
Effect conc.:
> 120 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
< 3.5 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
cell number
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
6.3 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Details on results:
- Exponential growth in the control (for algal test): yes
Results with reference substance (positive control):
- Results with reference substance valid? Yes
Reported statistics and error estimates:
EyC50 and ErC50 were calculated using regression equations. NOEC Confidence limits were calculated using NCSS 2000, and Duncan's Multiple Comparison Test.

Applicant's summary and conclusion

Conclusions:
The 72 hour 50% yield inhibition concentration of IN-DCB80 to P. subacapitata is 54.49 mg/L, with 95% confidence limits of 54.063-54.917 mg/L, and a NOEC of 3.5 mg/L. The 72 hour 50% rate inhibition concentration of IN-DCB80 to P. subcapitata is > 120 mg/L, with a NOEC of 6.3 mg/L.